Current steering using mad&#39;s



United States Patent 3,407,308 CURRENT STEERING USING MADS David Nitzan, Palo Alto, Calif., assignor, by mesne assignments, to AMP Inc., Harrisburg, Pa., a corporation of New Jersey Filed Oct. 8, 1964, Ser. No. 402,476 6 Claims. (-Cl. 30788) Circuits using magnetic cores for the purpose of current steering are finding extensive use in present-day technology. Effectively, these circuits are used where a large number of loads are present and it is desired to switch current into one or the other of every pair of loads. A magnetic core can act as a type of a gate requiring either a coincidence of inputs before it applies current to the load to which it is coupled, or storing inputs which may arrive in random fashion until the required number or sequence of inputs has occurred, after which the core can apply current to its load. One of the problems which arises in these systems is that of the cross feed of current between the several drive windings coupled to a core, which can interfere with the proper operation of other cores which are linked by these windings. By way of illustration, if a core circuit arrangement is of the type in which the core is to accumulate inputs after which, in response to a clearing drive, it will provide current to a load, then the currents which are applied to the input windings do induce other currents in the clearing windings with consequent deterioration in the functioning of the cores.

An object of the present invention is the provision of a magnetic core current steering arrangement which minimizes undesired couplings between windings on a core to the point where the performance of the core is left undeteriorated.

Yet another object of the present invention is the provision of a novel current steering magnetic core circuit arrangement.

Yet another object of the present invention is the provision of a novel current steering circuit arrangement using multiapertu-re cores.

The foregoing and other objects of this invention may be achieved in an arrangement wherein by way of illustration, two loads are provided which are to be selectively driven either by the output from one or the other of two cores or one or the other of the output apertures of a'single rnultiaperture core. Provision is made for coupling the load selecting windings to the output apertures of the multiapefiure cores in a manner so that currents in these windings do not affect magnetic flux circulating around the major aperture of the multiaperture cores whereby the clear driving winding coupled to these cores passing through their major apertures as substantially no voltage induced therein.

The novel features that are considered characteristic of this invention are set forth with particularity in the appended claims. The invention itself both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings, in which:

FIGURE 1 is a circuit diagram of an embodiment of this invention;

FIGURE 2 is a wave shape diagram of drive currents shown to assist in an understanding of the operation of FIGURE 1 and FIGURE 3; and

FIGURE 3 is a circuit diagram of a second embodiment of this invention.

In order to obtain isolation between the load selecting windings on a magnetic core and the winding which finally drives that magnetic core for the purpose of inducing enough current in an output winding to drive a selected load, in accordance with this invention, multiaperture cores are employed. Further, in accordance with this invention, the load selecting windings are coupled to the output apertures of multiaperture cores in a manner so that any flux changes which occur in the core in response to current flowing through the load selection windings have a substantially minimal effect upon the magnetic flux circulating through the magnetic material of the core surrounding its main aperture. The multiaperture core, as is well known, may be made from magnetic ferrite material having the property that its hysteresis characteristic is substantially rectangular. Therefore, the core presumably has two states of remanent flux.

in FIGURE 1, by way of illustration and not by way of limitation, there is shown a circuit diagram of an embodiment of this invention wherein in one stage it is desired to drive one or the other of two loads 10, 12, in response to outputs from one or the other of two multiaperture magnetic cores respectively 14, 16. The multiaperture cores 14, 16 shown in FIGURE 1 are of the well-known type having an input aperture respectively 14A, 16A, an output aperture respectively 14B, 16B, and central or main apertures respectively 14M, 16M. The reference numerals 1, 2, 3, 4 are applied to the magnetic material respectively between the input aperture and the outside edge of the core, between the input aperture and the main aperture of the core, between the main aperture of the core and the output aperture, and between the output aperture and the outside edge of the core. These regions of the core are known as legs and this is a nomenclature that will be used hereafter.

A preset Winding 20 is inductively coupled to the cores 14 and 16 respectively. It is wound on core 14 by passing through the input aperture 14A, thereafter it is wound on core 16 by passing through the input aperture 16A. Thereafter, the winding 20 serves the function of holding the outside legs (legs 4) of the cores 14 and 16 in a clear state by passing through the output aperture 16B of core 16 and the output aperture of 14B of core 14- The winding 20 then extends to the two cores of a succeeding stage. Winding 20 is driven from a preset pulse source 22 which applies a current pulse thereto, as represented by the Wave form 22A in FIGURE 2. In response to thiscurrent pulse, the magnetic cores 14 and 16 are preset to that state of magnetic remanence after which they can be primed by the application of a proper magnetomotive force to the magnetic material around the output aperture. The operation of the preset winding for the purpose of presetting the core prior to priming, and also to hold the core, is well understood. The preset drive is applied to the cores which have been previously cleared. The function of the hold winding is to restrict the flux change, occurring due to the preset drive, to the region of the multi-aperture core magnetic material which is around the major aperture or central aperture, and not to let it extend through the leg 4 material.

Two pulses are applied for the purpose of determining which of the two loads 10, 12 will be primed. A sampling pulse, which is generated by a source 24, is applied to a sampling winding 26. The sampling winding 26 is inductively coupled to the core 14 first passing through the output aperture and then around the leg 3 through the major aperture and then through the output aperture again, and thereafter on to the succeeding stage. The sampling pulse is represented by the wave form 24A in FIGURE 2, and occurs after the preset pulse.

The elfect of the sampling pulse, if it occurs alone, is to prime core 14. There may also be generated a transfer pulse by a transfer logic circuit 28, which occurs substantially coincidentally and coextensively with the sampling pulse. This transfer pulse is represented by the wave form 28A in FIGURE 2. The transfer logic circuit pulse is applied to a transfer winding 30. This winding is coupled to core 14 by passing through the output aperture with a sense so that when it is driven it produces a magnetomotive force which overrides the magnetomotive force which is produced by the sampling winding 26 when it is driven, and thus preventing priming in core 14. The transfer circuit winding 30 is also coupled to the magnetic core 16 by passing through the output aperture 163 with a sense so that the magnetic core 16 can be primed when the transfer winding 30 is energized.

From the foregoing description, it may be seen that energization of the sampling winding 26 alone results in priming core 14. Energization of the sampling winding 26 and transfer winding 30 together results in priming core 16. An output winding 32 is inductively coupled to core 14 by passing through its output aperture 14B. One end of the output winding 32 connects to a junction with another output winding 34 and then through a diode 36 to ground. The output winding 34 is inductively coupled to core 16 by passing through the output aperture 16B. Winding 32, after passing through aperture 14B connects to a diode 38 and then to the load 10, and thereafter to succeeding stages which are driven by the same current. Winding 34 after passing through the output aperture 16B connects to a diode 40 which is connected to the load 12, and thereafter joins with the connection to the other side of the load to a subsequent stage which is to be driven.

To complete the structure required to operate the embodiment of the invention, a clearing winding 42 is provided which is inductively coupled to the cores 14, 16 by passing through their main or central apertures respectively 14M, 16M. Thereafter, the clearing winding 42 is connected to the junction 35 to which the two output windings 32, 34 are connected. A current pulse is applied to the clearing winding 42 from a clearing pulse source 44. This current pulse is represented by the wave form 44A in FIGURE 2. It occurs after the occurrence of either of the wave forms 24A or 28A. The clearing pulse source applies a current pulse to the winding 42 which has the function of driving both cores 14 and 16 to their clear states. When this happens, the voltage induced in the one of the two output windings 32 or 34 is coupled to a core which has been previously primed.

To review the operation of this system', a preset pulse 22A sets all the cores in the system. Each core is set via legs 1, M (the magnetic material around the main aperture) and 3 while leg 4 is held. If a sampling pulse occurs in the absence of a transfer pulse, core 14 is primed. In the presence of a transfer pulse, the effect of the sampling pulse is overridden and core 16 is primed. A clearing pulse, which occurs thereafter, clears both cores 14 and 16 and induces current in the output winding coupled to the one of the two cores which is primed, unblocking the corresponding diode and the load. The other diode is blocked. Thus, the current is steered to the desired load.

Decoupling during sampling time is achieved because flux changes occur around the minor aperture and no voltage appears across the clearing winding 42 since there are no flux changes occurring in the legs M of material. Any voltage which may be induced in the clearing winding due to flux changes in the material of legs 3 have polarity such that the diode corresponding to the primed core is blocked, and thus no current will flow in the clearing winding 42. Decoupling during clearing time is achieved'because the sampling winding 26 links only leg 3 of core 14 where no flux switching takes place during the clearing time. A voltage which may be induced in the transfer winding is permissible since each transfer winding is individual to a set of cores and is not coupled to any other succeeding stages. The transfer pulse may terminate either together with or after the sampling pulse, which should not terminate before the sampling pulse 4 in view of its function of blocking the effects of the sampling pulse.

FIGURE 3 shows a circuit arrangement which is similar to the one shown in FIGURE 1 using, however, only a single core 60 with a single input aperture 60A and two output apertures respectively 60B, 60C. The structure in FIGURE 3 which performs the identical function as structure in FIGURE 1 is given the same reference numerals. The preset winding 20 after passing through the input aperture 60A for the purpose of performing the preset function thereafter passes through the output apertures 60B, 60C for the purpose of performing the holding function of the outer legs. The clearing winding 42 passes through the central aperture of the magnetic core 16 and then is connected to the junction which is-connected to ground to the diode 36. The sampling winding 26 is coupled to core 60 through the output aperture 60C so that when it is energized from the sampling pulse source 24, it can prime core 60, more specifically the magnetic material around the output aperture 60C of core 60. The transfer winding 30 is coupled to the magnetic material surrounding output aperture 60C with a sense to oppose the effects of the sampling winding, should both windings be energized simultaneously. Transfer winding 30 thereafter extends to be inductively coupled to the core 60 by passing through the output apertures 60B and 60C. This time the sense of the coupling is such that transfer windings will prime the magnetic material surrounding output aperture 60B, and prevent priming in aperture 60C.

The operation of this system shoWn in FIGURE 3 is identical with that shown in FIGURE 1. Accordingly, it need not be redescribed. The decoupling during sampling time and during clearing time between the windings on the core is present for the same reasons as were given previously. There is no flux change around the major aperture during sampling time except in the leg 3 region. Whatever voltage may be induced in winding 32 or winding 34 has a polarity such that diode 38 or diode -can block the flow of current in the clearing winding. Since the sampling winding only links leg 3 of the core, theenergization of the clearing winding does not induce any current in the Sampling winding since no flux change occurs within leg 3 during the clearing operation. Any current flow within the transfer winding 30 which can occur during the clearing time is inconsequential, since this winding is singular to each stage of the apparatus.

There has accordingly been described and shown herein a novel, useful arrangement for current steering using magnetic cores which provides isolation between windings used on those cores.

What is claimed is:

1. Apparatus for steering current to a predetermined one'of two loads comprising multiaperture magnetic core means having at least an input aperture, a main aperture, and two separate output apertures, said multiaperture magnetic core means having a preset state, a first and second prime state, and a clear state, means for driving said multiaperture core means to said preset state including a preset winding inductively coupled to said input aperture, means for selectively priming said magnetic core means to its first priming state or to its second prime state including a sampling winding inductively coupled to said magnetic means by passing through said first output aperture for driving said magnetic core means to its first prime state when energized, and transfer winding means inductively coupled to said first and second output apertures for driving said magnetic means to its second prime state and preventing its being driven to its first prime state by said sampling winding means when energized, a first load winding coupling said one of said two loads to said magnetic means by passing through said first output aperture for applying current to said one of said two loads when said magnetic means is driven from its first prime to its clear state, a second load winding means coupling said second load to said magnetic means by passing through its second output aperture for applying current to said second load when said magnetic means is driven from its second prime state to its clear state, and clear winding means coupled to said magnetic means by passing through its main aperture for driving said magnetic means to its clear state.

2. Apparatus as recited in claim 1 wherein said magnetic means comprises two multiaperture cores.

3. Apparatus as recited in claim 1 wherein said magnetic means comprises a single multiaperture core having a single input aperture, and a first and second output aperture.

4. Apparatus as recited in claim 1 wherein said clear winding means includes a diode serially connected therewith with a polarity to block current flow responsive to voltages induced therein when either of said first or second multiaperture core means is driven from its preset to its prime state.

5. Apparatus for steering current to a predetermined one of two loads comprising a first and a second multiaperture core, each said multiaperture core having an input aperture, a main aperture, and an output aperture, said multiaperture core being made of magnetic material having substantially rectangular hysteresis characteristics, said multiaperture cores having a reset state of rernanence, a prime state of remanence and a clear state of remanence, preset winding means inductively coupled to the input apertures of said multiaperture magnetic core for driving them to their preset state, means for priming one of said two multiaperture cores including sampling pulse winding means inductively coupled to said first core by passing through its output aperture for priming said first core when energized, and transfer circuit winding means for preventing the priming of said first core when energized and for priming said second core by passing through the output aperture of said first core with a winding sense relatively opposite to the winding sense of said sampling winding means and passing through the output aperture of said second core with a sense for priming said second core when energized, a first load winding means coupling said first load to said first multiaperture core means for applying a current to said load when said first multiaperture core means are driven from its prime to its clear state, a second load winding means coupling said load to said second multiaperture core for applying a current to said second load when said second multiaperture core is driven from its prime to its clear state, and clearing winding means inductively coupled to said first and second multiaperture cores by passing through their main apertures for driving said first and second multiaperture cores to their clear states.

6. Apparatus for steering current in a predetermined one of two loads comprising a multiaperture core having an input aperture, a central main aperture, a first output aperture and a second output aperture, said multiaperture core having a preset state of remanence, a first prime state of remanence, a second prime state of remanence, and a clear state of remanence, means for driving said multiaperture core to its preset state including preset winding means coupled to said magnetic core by extending through said input aperture and successively through said output apertures for transferring said core to its preset state when energized, means for selecting the one of two loads to be driven including a sampling winding means coupled to said core by passing through said first output aperture for driving said core to its first prime state when energized, transfer winding means coupled to said core by passing through said first output winding and said second output winding for preventing said core from being transferred to its first prime state but transferring said core to its second prime state when energized, a first output winding coupling said one of said two loads to said core by passing through said first output aperture, a second output winding coupling the other of said two loads to said core by passing through said second output aperture, and means for driving said multiaperture core to its clear state to apply current to one of said two loads in accordance with the one of two prime states to which said core has been driven comprising a clearing winding passing through said multiaperture core main aperture and a diode connected in series with said clearing winding for preventing current flow therethrough when said core is driven to its first or its second prime state.

References Cited UNITED STATES PATENTS 3,150,354 9/1964 English 340-174 3,289,185 11/1966 Crane et al 340-174 3,331,965 7/1967 Andreasen 340174 BERNARD KONICK, Primary Examiner.

J. F. BREIMAYER, Assistant Examiner. 

1. APPARATUS FOR STEERING CURRENT TO A PREDETERMINED ONE OF TWO LOADS COMPRISING MULTIAPERTURE MAGNETIC CORE MEANS HAVING AT LEAST AN INPUT APERTURE, A MAIN APERTURE, AND TWO SEPARATE OUTPUT APERTURES, SAID MULTIAPERTURE MAGNETIC CORE MEANS HAVING A PRESENT STATE, A FIRST AND SECOND PRIME STATE, AND A CLEAR STATE, MEANS FOR DRIVING SAID MULTIAPERTURE CORE MEANS TO SAID PRESET STATE INCLUDING A PRESET WINDING INDUCTIVELY COUPLED TO SAID INPUT APERTURE, MEANS FOR SELECTIVELY PRIMING SAID MAGNETIC CORE MEANS TO ITS FIRST PRIMING STATE OR TO ITS SECOND PRIME STATE INCLUDING A SAMPLING WINDING INDUCTIVELY COUPLED TO SAID MAGNETIC MEANS BY PASSING THROUGH SAID FIRST OUTPUT APERTURE FOR DRIVING SAID MAGNETIC CORE MEANS TO ITS FIRST PRIME STATE WHEN ENERGIZED, AND TRANSFER WINDING MEANS INDUCTIVELY COUPLED TO SAID FIRST AND SECOND OUTPUT APERTURES FOR DRIVING SAID MAGNETIC MEANS TO ITS SECOND PRIME STATE AND PREVENTING ITS BEING DRIVEN TO ITS FIRST PRIME STATE BY SAID SAMPLING WINDING MEANS WHEN ENERGIZED, A FIRST LOAD WINDING COUPLING SAID ONE OF SAID TWO LOADS TO SAID MAGNETIC MEANS BY PASSING THROUGH SAID FIRST OUTPUT APERTURE FOR APPLYING CURRENT TO SAID ONE OF SAID TWO LOADS WHEN SAID MAGNETIC MEANS IS DRIVEN FROM ITS FIRST PRIME TO ITS CLEAR STATE, A SECOND LOAD WINDING MEANS COUPLING SAID SECOND LOAD TO SAID MAGNETIC MEANS BY PASSING THROUGH ITS SECOND OUTPUT APERTURE FOR APPLYING CURRENT TO SAID SECOND LOAD WHEN SAID MAGNETIC MEANS IS DRIVEN FROM ITS SECOND PRIME STATE TO ITS CLEAR STATE, AND CLEAR WINDING MEANS COUPLED TO SAID MAGNETIC MEANS BY PASSING THROUGH ITS MAIN APERTURE FOR DRIVING SAID MAGNETIC MEANS TO ITS CLEAR STATE. 